Question

If $KCl$ is 50% ionised in the aqueous solution what will be the van't Hoff factor of $KCl$ in the solution?

• A. $1$
• B. $2$
• C. $1.25$
• D. $1.5$

Answer 1

The correct option is D $1.5$

$KCl\left(aq\right)\rightleftharpoons K^{+}+C{l}^{-}Initially:C00Eqb:C-C\alpha C\alpha C\alpha$

$i=\frac{\text{No. of moles after dissociation}}{\text{No. of moles before dissociation}}$

$i=\frac{C-C\alpha +C\alpha +C\alpha }{C}i=\frac{C+C\alpha }{C}=1+\alpha$
Given that :
$\alpha =0.5$
$i=1+\left(0.5\right)i=1.5$